Current techniques for producing graphene and graphene oxide are mainly: chemical vapor deposition method (CVD), oxidation-reduction method and other methods. In prior art, graphite or graphene products are used as starting materials to produce graphene oxide. The method has low yield, high cost, heavy pollution, and low product quality, and the characteristics of the product are difficult to be controlled. For example, current methods for producing graphene have the disadvantages and drawbacks as follows: for the CVD method, severe requirement on production process and high cost; for the oxidation-reduction method, complicated process and the requirement of heavy metal ions. Sulfonated graphene, an important type of functionalized graphene, is increasingly used in various graphene applications. There is still a demand for a new method for preparing sulfonated graphene on a large scale. Meanwhile, there are still a large number of demands for sulfonated graphene having homogenous properties.